Radiotelegraphy



R. R. BEAL.

RADIOTELEGRAPHY. APPLICATION HLED pm 8. 1917.

1,350,695 Patented Aug. 24, 1929.

INVENTOR H. R. BE/ILI UNITE. SATES PATNT OFFICE.

RALPH R. BEAL, OF PALO ALTO. CALIFORNIA, ASSIGNOR TO FEDERAL TELEGRAPH COMPANY, OF SAN FRANCISCO, CALIFORNIA, A.

CORPORATION OF CALIFORNIA.

RADIOTELEGRAPHY.

Application filed October 8, 1917.

To all ll 110m it may concc'm Be it known that I, RALPH R. HEAL, a citizen of the United States, and a resident of Palo Alto, Santa Clara county, State of California, have invented certain new and useful Improvements in lladiotelegraphy, of which the following is a specification.

The invention relates to transmission systems and particularly to a means of signaling.

An object of the invention is to provice simple and eiiicient signaling system for radio telegraphy transmission stations,

The invention possesses other advantageous features, some of which, with. the fore going, will be set forth at length in the following description, Where I shall outline in full, that form of the invention which i: ha've selected'i or illustration in the drawing accompanying and tormingpart of the presentspecification. in said drawingl have shown one specific form of my invention, but it is to be understood that I do not limit myself to such form, since the invention as expressed in the claims may be embodied in a plurality of forms.

Referring to said drawing:

The figure is a'diagrammatic representation or" a radio telegraph transmission system embodying my invention. The system includes a suitable source of oscillations, preferably continuous oscillations, such as the are 2 which operates in an atmosphere or" hydrogen. The are generator is grounded on one side. preferably the negative, and is connected on the other side to the antenna 3 through the variable inductance 4-. Direct current is supplied to the are by the generator 5 and a choke coil (3 is arranged in the lead 7 connected to the antenna side of the arc. The are is subjected to a strong transverse magnetic field which may be produced in any desirable manner as by the magnetcoils 8. which may be se 'iarately excited by the generator 9, or which may be arranged in the lead 7.

an inductance 12 and a Shunted across the arc is a second oscillatory circuit or absorbing circuit, containing capacity 13, this circuit having slightly different electrical time constants than the antenna circuit. When an arc is shunted by two oscillatory circuits having different electrical time constants, it may be made to oscillate upon one circuit or Specification of Letters Patent.

Patented Aug. 24, 1920.

Serial No. 195,259.

the other, and not on both at'the same time, and will oscillate upon the circuit upon which it is aisiest to oscillate, to the total neglect of the other. By varying the electri cal constants oi the absorbing circuits, this circuit is chosen or neglected and conse quently the radiating circuit is neglected or chosen. l

The present invention contemplates varying the resistance of the absorbing circuit and this resistance is inserted without open ing or closing the absorbing circuit. The constants of the absorbing circuit are such that when the resistance is inserted, the arc will oscillate upon the radiating circuit and when the resistance is Withdrawn, the arc will oscillate on the absorbing circuit. In stead of introducing the resistance directly into the absorbing circuit, I introduce into the system a resistance which has the equivalent eii ec't oi introducing the resistance directly into ,the absorbing circuit,'and this is introduced in such manner that sparking or arcing at the contacts is practically avoided.

ifihunting several of the turns of the inductance 12 of the absorbing circuit is a circuit containinga resistance 1% and a signaling key 15. With the key closed, a radio frequency current will flow through the resistance. causing an energy loss, so that the resistance has the equivalent eil'ect of being inserted directly in the absorbing circuit. The current through the resistance is probably not only the absorbing circuit current, but also a certain amount of induced current, due to the transformer action 01 the induct ance 12, which becomes in effect an autotransformer. I prefer to make the value of. the resistance in ohms substantially equal to the reactance in ohms at radio freipiency, of the turns of the inductance which are shunted by the resistance circuit in order to cause a maximum energy loss in the re sistance.

When the key is open, the arc oscillates upon the absorbing circuit and when the key is closed the arc oscillates upon the radiating circuit.

1 claim:

1. In a radio telegraphy transmission sy tem, a source of oscillations, a radiating circuit and an absorbing circuit containing inductance both in parallel and shunted around said source, a circuit containing resistance arranged in shunt around said inductance, and means for opening and closing the resistance circuit.

2. In a radio teiegraphy transmission system, a source of oscillations, a radiating cir'cuit'connected to said source, an absorbing circuit containing inductance, shunted around said source, and a key controlled circuit containing resistance arranged in shunt 10 around said inductance, the value of the resistance in ohms approximating the 'reactance in ohms at radio frequency of; the shunted inductance, to cause a maximum energy loss in the resistance when the resistance circuit is closed.

In testimon whereof I have hereunto set my hand at onoiulu, Territory of Hawaii, this 8th day of September, 1917.

RALPH R. BEAL. 

